820-00165 spins orange light, No backlight Board boot loop after hitting login screen

[2informaticos]

"smc dcin vsense is 18v
smc pbus vsense is 8.5v"
Are you sure???
SMC is fried then; it cannot recieve such overvoltage on any input.
Be sure to measure on C5504/14...

 

[KuroAkita]

C5505 reads 1.426
c5514 reads 3.119
but q5510 on pin 3 measure 18.5v

 

[2informaticos]

"C5505 reads 1.426"
If is C5504, that's good.

C5514 voltage is good enough.
Check the sensors from pages 41 & 43 too.
Pay atention to A/BMON sensors...

Be sure R7051/52 have both correct value.

 

[KuroAkita]

I could not find r7052/51
but on amon sense r5431 i get 0.241
on bmon sense r5472 1.051

 

[2informaticos]

"Be sure R7051/52 have both correct value."
Sorry for my error; read in other way...
Be sure R7151/52 have both correct value.

 

[KuroAkita]

i presume you mean in dc mode? both are reading 0 volts

 

[2informaticos]

There are very low values, use ohm scale...

 

[KuroAkita]

Okay just plugged it in to go measure those values, I'm no longer getting a light or fan spin.

 

[KuroAkita]

I should mention before posting this I tried another DC board and flex and charger

 

[2informaticos]

This board is a nightmare.
However, I do not understand why did you want to measure ohm mode on a powered board!!!

 

[KuroAkita]

my mistake, I should i have said i was plugging it back in to double check the dc values just incase i measured them wrong.
Any idea where to go from from here? No light no fans =/ or do you think this is a done board,

 

[2informaticos]

Probably hopeless repair.
But if you got some experience from it, is no time waste at least...

Post voltages for 3V42 and PPBUS_G3H.
If no volt, post resistance to ground; allow 20s after power is removed.

 

[KuroAkita]

It is good experience yes. And being new to this, thats very much what i need. Just to check to check oltages for 3v2 and ppbus_g3h i put one probe on earth and one probe on the corrosponding component.
(ill check schematic to figure out which components that is). How do you know what voltages parts should be outputing? I originally got the 25v i spoke of a the start of this thread from the schematic.

 

[2informaticos]

None of mentioned points can have 25V.
No idea where did you get that high voltage...

 

[KuroAkita]

I must have misread the schematic or something. Ill get those measurements now.

 

[KuroAkita]

Okay, im practically getting 0 volts on ppbus g3h. i measured this from f7700 and f7140
on pp3v42_g3h im getting 3.419 volts. measured this on c5120 r5127

 

[2informaticos]

Resistance to ground on F7140?
Post some voltages for ISL6259, basic pins 2, 3, 9, 12, 13, 15, 17, 18, 19, 20, 27, 28.

 

[KuroAkita]

Just to check, resistance to ground is measured via the ohm selection and with the board being unpowered. black pin on ground red on output? or both on either side of the component.

 

[2informaticos]

Red probe to ground, diode mode.
Switch to ohm mode for very low value, like measuring between pins 17/18 and 27/28.
Or in case of VCORE power rail, which can drop untill 1 ohm...

 

[KuroAkita]

F7140 is 0.152v on pin 2
isl6259
2 is 0.614v
3 is 0.512v
9 is 0.705v
12 is 0.306v
13 is 0.481v
15 is 0.724v
17 is 0.659 k ohm
18 is 0.655 k ohm
19 is 0.267v
20 is 0.269v
27 is 9.47 m ohm
28 is 5.81 m ohm


think that about covers it. On this boad its called u7100, just checking thats what you meant as there is no isl6259 on this board.
weve replaced this before but maybe it was replaced with a bad one.